// The MIT License (MIT) // // Copyright (c) Itay Grudev 2015 - 2018 // // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to deal // in the Software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN // THE SOFTWARE. #include #include #include #include #include #include #include "singlecoreapplication.h" #include "singlecoreapplication_p.h" /** * @brief Constructor. Checks and fires up LocalServer or closes the program * if another instance already exists * @param argc * @param argv * @param {bool} allowSecondaryInstances */ SingleCoreApplication::SingleCoreApplication( int &argc, char *argv[], bool allowSecondary, Options options, int timeout ) : app_t( argc, argv ), d_ptr( new SingleCoreApplicationPrivate( this ) ) { Q_D(SingleCoreApplication); // Store the current mode of the program d->options = options; // Generating an application ID used for identifying the shared memory // block and QLocalServer d->genBlockServerName(); #ifdef Q_OS_UNIX // By explicitly attaching it and then deleting it we make sure that the // memory is deleted even after the process has crashed on Unix. d->memory = new QSharedMemory( d->blockServerName ); d->memory->attach(); delete d->memory; #endif // Guarantee thread safe behaviour with a shared memory block. d->memory = new QSharedMemory( d->blockServerName ); // Create a shared memory block if( d->memory->create( sizeof( InstancesInfo ) ) ) { // Initialize the shared memory block d->memory->lock(); d->initializeMemoryBlock(); d->memory->unlock(); } else { // Attempt to attach to the memory segment if( ! d->memory->attach() ) { qCritical() << "SingleCoreApplication: Unable to attach to shared memory block."; qCritical() << d->memory->errorString(); delete d; ::exit( EXIT_FAILURE ); } } InstancesInfo* inst = static_cast( d->memory->data() ); QTime time; time.start(); // Make sure the shared memory block is initialised and in consistent state while( true ) { d->memory->lock(); if( d->blockChecksum() == inst->checksum ) break; if( time.elapsed() > 5000 ) { qWarning() << "SingleCoreApplication: Shared memory block has been in an inconsistent state from more than 5s. Assuming primary instance failure."; d->initializeMemoryBlock(); } d->memory->unlock(); // Random sleep here limits the probability of a collision between two racing apps qsrand( QDateTime::currentMSecsSinceEpoch() % std::numeric_limits::max() ); QThread::sleep( 8 + static_cast ( static_cast ( qrand() ) / RAND_MAX * 10 ) ); } if( inst->primary == false) { d->startPrimary(); d->memory->unlock(); return; } // Check if another instance can be started if( allowSecondary ) { inst->secondary += 1; inst->checksum = d->blockChecksum(); d->instanceNumber = inst->secondary; d->startSecondary(); if( d->options & Mode::SecondaryNotification ) { d->connectToPrimary( timeout, SingleCoreApplicationPrivate::SecondaryInstance ); } d->memory->unlock(); return; } d->memory->unlock(); d->connectToPrimary( timeout, SingleCoreApplicationPrivate::NewInstance ); delete d; ::exit( EXIT_SUCCESS ); } /** * @brief Destructor */ SingleCoreApplication::~SingleCoreApplication() { Q_D(SingleCoreApplication); delete d; } bool SingleCoreApplication::isPrimary() { Q_D(SingleCoreApplication); return d->server != nullptr; } bool SingleCoreApplication::isSecondary() { Q_D(SingleCoreApplication); return d->server == nullptr; } quint32 SingleCoreApplication::instanceId() { Q_D(SingleCoreApplication); return d->instanceNumber; } qint64 SingleCoreApplication::primaryPid() { Q_D(SingleCoreApplication); return d->primaryPid(); } bool SingleCoreApplication::sendMessage( QByteArray message, int timeout ) { Q_D(SingleCoreApplication); // Nobody to connect to if( isPrimary() ) return false; // Make sure the socket is connected d->connectToPrimary( timeout, SingleCoreApplicationPrivate::Reconnect ); d->socket->write( message ); bool dataWritten = d->socket->flush(); d->socket->waitForBytesWritten( timeout ); return dataWritten; }